Design
I was at the office, about to go out and grab lunch from a nearby restaurant. Like many companies, I work in one that uses a service to manage our budget for paid meals. Using a mobile app, I can generate a 5-digit code, which I give to the restaurant, and it automatically charges my account. Beautiful, simple, and effective.
I was standing in line, tapping my fancy code-generation button, and after a few seconds, I witnessed a (probably) rare event. The food app suddenly showed me that my order had been accepted and confirmed. Did someone hijack my code? At this point, I thought this was just a client bug. I regenerated a new code and went on with my order.
